547.462.3-052.2

NOTE ON THE PREPARATION OF FUMARIC NITRILE BY

W. GAADE.

An improved method for the preparation of fumaric nitrile is described, giving a considerably higher yield than the method known from the literature.

In the course of an investigation we needed fumaric nitrile HC-CN

/I NC-CH

as an intermediate product for further syntheses. The compound not being commercially available, we had to prepare it in our laboratory. A simple method of preparing fumaric nitrile starts from fumaric acid which is converted into its amide and the latter dehydrated to fumaric nitrile:

HC-COOH HC-CONH2 HC-CN II + 2 HzO + NC--CH

/I H2NOC-CH

/ I HOOC--CH

However, at that time we had no fumaric acid at our disposal. W e therefore had to use the method described by J e n n e n I ) , namely of allowing trans- diiodoethene to react with cuprous cyanide:

HCI HC-CN 11 + C U ~ ( C N ) ~ + Cu212 + I/

ICH NC-CH

J e n n e n claims a yield of 30 %, which did not satisfy us. For this reason we not only repeated his method, but we also modified it slightly. In this way we obtained a yield of 19 % using the original method and 59 "/o according to our own method. Consequently it seems worth while toadescribe the latter method here.

EXPERIMENTAL PART. I. Trans-diiodoefhene.

CaC, + H,O +. CaO + GH, C2H, + I, + C2H212

Trans-diiodoethene was prepared by the interaction of iodine and acetylene (ethine). A continuous stream of acetylene, prepared from calcium carbide and water 2) . was led into a flask containing iodine and ethyl alcohol 3) at room temperature during a week. 'The crystalline mass formed was separated from the liquid by decantation, washed with dilute sodium hydroxide and recrystallized from ethyl alcohol. The decanted liquid was also treated with diiute NaOH. which gave a yellowish suspension, out of which after some time yellow oily drops and a brown crystal mass separated. The latter was recrystallized from alcohol. The total yield of frans-diiodoethene from the original crystals and those obtained froln the liquid was 63 yo referred to the iodine (68.9 g from 100 g of iodine).

White fibrous ncedles, discolouring in daylight to a light pink and consequently kept in a brown container. M.p. 73" C according to the literature 4 ) .

J. J e n n e n, Bull. classe sci Acad. roy. Belg. (5) 22, 1171 (1936). *) J. A. M a t h e w s, J. Am. Chem. SOC. 22, 106 (1900). 3, H. B i l t z , Ber. 30, 1207 (1597). 4, Cf. H. P. K a u f m a n n , Ber. 55, 263 i1922).

W . Gaade. Note on the preparation of fumaric nitrile. --

824 ._____

11. Fumnric nitrile. CzHJz + C y ( C N ) , + CqI , + C,H,((=N),.

a . lennen's method. 1.8 g of cuprous cyanide and 2.8 g of trans-diiodoethene were heated for 14 hours in an

oil-bath (temp. 160" C) in a 100 cm3 round-bottomed flask fitted with a long reflux condenser. The fumaric nitrile formed had then sublimed on the cork of the flask and in the tube. It was recrystallized from hot water, and gave 0.15 g of fumaric nitrile, melting at 92.2"-95.5" C. J e n n e n (loc. cit.) mentions a melting point of 96"-96.4'. which we also found by our method b.

The reaction mixture in the flask was heated further, according to J e n n e n , in vacuo at 200" C, which did not give rise, however, to more fumaric nitrile.

Neither did we obtain any more by extracting the mixture with hot water. Thus the total yield was 0.15 g = 19 yo.

b. Our method. 1.8 g of cuprous cyanide and 2.8 g of trans-diiodoethene were shaken horizontally in a

sealed tube for 5 hours at 150" C in a shaking machine. After cooling the tube was opened arid the contents were introduced into a retort. The latter was fitted with a capillary, evacuated and then heated on a sand-bath,. the temperature of which was 220" C. In this way the volatile products were distilled and regained as crystals which were recrystallized from hot water. The yield was 0.35 g of fumaric nitrile (= 45%) with m.p. 96.1"-96.5". This method obviously gives not only a better output than J e n n e n ' s method, but also a purer product.

A second experiment in which the time of heating was extended to 20 hours yielded 0.46 g ( = 59 yo). Recrystallization of the sublimated product gave directly 0.26 g of fumaric nitrile. another 0.20 g were obtained when the mother liquor was treated twice with ethyl ether. The mother liquor was then practically free of nitrile, as appeared from the test described by K e i s e r and K e s s 1 e r 6 ) . 'heating with a little KOH, addition of HNO, to an acid reaction, and then addition of AgNO, did not give any precipitate.

Fumaric nitrile was obtained here i3 the form of long, flat, white needles. The warm aqueous solution is very irritating to the eyes.

This investigation was carried out in the laboratories of the Rubber Foundation at Delft, (Netherlands).

(Received April 25th 1946).

6) E. H. K e i s e r and J. J. K e s s l e r , Am. Chem. J. 46, 527 (1911).